After one week on the job, members of the federal government’s new immunity task force say they are coming to grips with a towering wall of uncertainty that obscures the true extent of COVID-19 in Canada.

With more than 50,000 confirmed cases across the country and likely many more that have gone unreported, scientists are certain there is a population of individuals in Canada that have acquired some level of immunity to the new coronavirus that causes COVID-19. What remains unclear is the size and makeup of that population, the level of immunity it has developed and for how long.